Syrup having a red color has widely been used for the coloration of ice cream and for imparting a color and taste to, for instance, a variety of cocktails.
It has not conventionally been known to extract syrup having a red color from the red shiso and to use the same in such applications.
The inventors of this invention have found that syrup having a clear red color can be obtained by using red shiso as a raw material, and by extracting the red shiso while applying heat thereto and subsequently by treating the resulting extract with an acid. In particular, it has been unexpectedly found that when the red shiso is heat-treated, in advance, using salt water (the blanching treatment), the reddish tinge of the resulting syrup may be improved.
The syrup obtained from the naturally occurring food materials such as red shiso, by nature, does not adversely affect the human bodies and more specifically it is quite safe for the human body, as compared with synthesized ones.